Author Topic: Double "Click" when turning crankshaft 750 UPDATE Winner is (Read 3374 times)

ekpent · « **on:** September 28, 2009, 07:13:17 AM »

OK quick history. 75 750K-28,000 miles-history unknown-not been started in 6-7 years-did run (ever heard that one before

). So getting it ready for first start-pull carbs and soak parts.Set the tappetts,cam chain(made sure adjuster was working) and do a static time. PROBLEM- When I am turning the nut and crank by the points I am getting a fairly large "clicking" noise when I am approaching TDC on both the 1-4 and 2-3 reading on the advancer plate and another slightly quieter click slightly farther when passing past the numbers (1-4 or2-3).Have not been able yet to isolate where its coming from.(need a helper so I can get a good ear on it) Sounds like either behind the points plates area or maybe in the head ??. Did put my hand over intake rubber boots and seems to be drawing air.Never had this problem yet anybody else? or point me in a good place to start. Thanks---------Eric

tlbranth · « **Reply #1 on:** September 28, 2009, 09:42:59 AM »

It's probably slack in the cam chain changing from front to back as you go over a cam lobe.

ekpent · « **Reply #2 on:** September 28, 2009, 10:11:58 AM »

Thanks for the input on the cam chain.I did pull the tensioner,cleaned and lubed the shaft to make sure it was working properly and set according to specs,also set the timing and tappets to specs.Wondering if a valve problem would show itself at each 180 turn of the crank IE at both 1-4 and 2-3??

Gordon · « **Reply #3 on:** September 28, 2009, 10:24:11 AM »

I agree with tlbranth. When I installed the 650 cam in my 550 a few days ago I had the same clicking sound you described. At first I thought it was a valve issue and went back and reset all the valves, but it made no difference. Turns out I hadn't set the chain tensioner correctly and it was way too loose. I fixed that issue and the clicking stopped.

ekpent · « **Reply #4 on:** September 28, 2009, 10:30:41 AM »

Well Gordon its 2 for the cam chain so far. Will def check that out well when I get back to the shop.Have set those a million times but might have made a mistake. Did you get that "clicking" sound on both the 1-4 and 2-3 TDC area on every rotation?? Thanks for the help so far.-------Eric

Gordon · « **Reply #5 on:** September 28, 2009, 10:59:10 AM »

Quote from: ekpent on September 28, 2009, 10:30:41 AM

Well Gordon its 2 for the cam chain so far. Will def check that out well when I get back to the shop.Have set those a million times but might have made a mistake. Did you get that "clicking" sound on both the 1-4 and 2-3 TDC area on every rotation?? Thanks for the help so far.-------Eric

I didn't go as far as finding out exactly at what point the clicking was happening, but it was happening on every rotation and at the same spot. I did consider that it could be the chain, but figured it had to be the valves or tappets because of the sound it was making. I should have just checked the tension because it would have saved me the hassle of re-setting the valves.

ekpent · « **Reply #6 on:** September 28, 2009, 11:14:46 AM »

Alrighty. This is happening at the same exact spot on the rotation,though actually twice with every full turn.tdc at 1-4 and 2-3. I surely hope that is the problem and will report back when I can get her checked out again.If anybody has anything else to suggest or check when I go back I am all ears.

Gordon · « **Reply #7 on:** September 28, 2009, 11:35:10 AM »

You may need to manually apply some force to the tensioner to get it tight enough to take up the slack in the chain. I have to do that on my 750 because it's all the original parts and they're just too old, hard, and worn out to work right on their own.

ekpent · « **Reply #8 on:** September 28, 2009, 12:40:49 PM »

I have been checking the tensioner on the bikes I have bought lately and others I have and was surprised to see that they do get gummed up on the 750's and need a good cleaning ,lube to work correctly again. Noticed that on a post I read once,kind of dismissed it, about cleaning and also filing or smoothing the spot where the screw contacts,you may have contributed to that,but I am a BELIEVER now !! Cleaned this one but will give it a push also when I get back to it. Thanks for the input Gordon.-------Eric

Whaleman · « **Reply #9 on:** September 28, 2009, 04:52:14 PM »

A while ago I had an extensive post on how often tensioners are locked up and people think they are adjusting and nothing is really happening. I am glad you cleaned and lubed the shaft. Now, get a straight distributor wire connector rubber and fill the small end with silicone and slip it on. You do not need any silicone or glue to keep it on the engine only to seal the open end. It will keep water out. Once the cadium plating starts to rust it keeps rusting. It helps to polish to a mirror finish. Dan

ekpent · « **Reply #10 on:** September 28, 2009, 05:39:17 PM »

Hey Dan. That was a good post you wrote on the tensioners. Like I mentioned,I kind of dismissed it thinking with the spring and all they would not go bad.I would suggest to anybody restoring-working on one of these to take the time-undo 3 screws-pull it off and clean and check it out. Real easy when the carbs are already off.Thanks for the new tip. ----Eric

Don R · « **Reply #11 on:** September 28, 2009, 07:08:49 PM »

Check the advance weights behind the points plate.

Johnie · « **Reply #12 on:** September 28, 2009, 07:38:03 PM »

Where have I been? I have 3 750s's and did not know the cam chain tensioner should be pulled and cleaned? Cleaned with carb cleaner or what? Lubed with oil or grease? Thanks...

Whaleman · « **Reply #13 on:** September 28, 2009, 08:23:14 PM »

I can not find my old posts. My name was deleted when the last form update happened. While I have 100's of posts I had to start over. I can not find any of my old posts. Dan

Whaleman · « **Reply #14 on:** September 28, 2009, 08:30:43 PM »

http://forums.sohc4.net/index.php?topic=52277.0

OK, I found my old post. Under my old name. Dan

Johnie · « **Reply #15 on:** September 29, 2009, 04:55:46 AM »

Quote from: Whaleman on September 28, 2009, 08:30:43 PM

http://forums.sohc4.net/index.php?topic=52277.0

OK, I found my old post. Under my old name. Dan

Excellent and thanks for locating Dan. Guess I have three to check and clean.

ekpent · « **Reply #16 on:** September 29, 2009, 05:12:15 AM »

Will check those Don,thanks for the input. For some reason I feel pretty confident that its not going to be the cam chain. Will make some time to get to the shop today,check cam chain and take a peek behind the points plate and report back.Good day all----Eric PS Johnie-Found that those tensioner do not even have to be rusty to be working rather sluggishly.I clean them with some carb cleaner,blew them out dry and applied a thin layer of grease,cleaning the "ramp" before reinstall.

Johnie · « **Reply #17 on:** September 29, 2009, 06:23:16 AM »

Quote from: ekpent on September 29, 2009, 05:12:15 AM

Will check those Don,thanks for the input. For some reason I feel pretty confident that its not going to be the cam chain. Will make some time to get to the shop today,check cam chain and take a peek behind the points plate and report back.Good day all----Eric PS Johnie-Found that those tensioner do not even have to be rusty to be working rather sluggishly.I clean them with some carb cleaner,blew them out dry and applied a thin layer of grease,cleaning the "ramp" before reinstall.

Thanks for the info ek...will be getting at those. My K4 is especially noisey even after the adjust. I have a feeling that one is gummed.

Gordon · « **Reply #18 on:** September 29, 2009, 08:35:08 AM »

Quote from: ekpent on September 29, 2009, 05:12:15 AM

For some reason I feel pretty confident that its not going to be the cam chain.

I felt the same way until I readjusted mine and the clicking stopped.

ekpent · « **Reply #19 on:** September 29, 2009, 03:40:10 PM »

Well even an old dog learns new tricks.

Click is gone.

Tlbranth and Gordon were right on with their call. Even though I had cleaned the tensioner it still needed a small whack to seat the chain after sitting so long--- I will not forget that trick ,as well as you should not either,I have done a lot of 750's and will go back and check a few and the ones in the future for sure,If either one of you guys need a part or tid bit PM me and if I can help its yours-Thanks-------- Eric PS - Whale gets a shout also------good post.----and-She will live again - will post what comes out of the muffler when I fire her up soon

Gordon · « **Reply #20 on:** September 29, 2009, 05:44:06 PM »

I'm glad it worked out. I was keeping my fingers crossed that I wansn't going to be eating crow when you figured out it was something other than the cam chain.

It was a learning experience for me, too. Out of the dozen plus motorcycle engines I've worked on I've never had the cam chain make that noise before. It's kind of a funny coincidence that it happened to us both within a few days of each other.

ekpent · « **Reply #21 on:** September 29, 2009, 07:07:24 PM »

+1 Gordon, You and the other fella called it. I to have worked on a bunch of these motors but have never had that sound before a start-up. Not what you want to hear before you put the carbs back on and give it the juice.Feel better and give a shout out to Dan-Whaleman for looking into that whole 750 cam chain deal.I think they need more attention then we think.Great Forum and Super people--Eric

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Author Topic: Double "Click" when turning crankshaft 750 UPDATE Winner is (Read 3374 times)